Awesome image of a water bubble in space

The following photograph, NASA’s image of the day, is not only awesome, it illustrates two very cool scientific ideas that explain why the water bubble is floating, and why it doesn’t break.

NASA astronaut Kevin Ford, Expedition 34 commander, watches a water bubble float freely between him and the camera. (NASA)

1. Microgravity: The International Space Station is well within Earth’s gravitational field. In fact if it were stationary it would feel about 90 percent of the gravity we feel standing on the Earth. However, because the station is in “free fall” around the planet, objects aboard it are weightless. Thus, the ball of water is floating in the picture.

2. Surface tension: Outside of mercury, water has the greatest surface tension of any liquid. This is because the bonds between water molecules are very strong, and at the surface they’re even stronger because there are fewer water molecules to cling to. This surface layer creates a considerable barrier between the water and the atmosphere. So the water bubble doesn’t break.